Materialisation, William Crookes and Katie King, 1874 (b/w photo)

Katie King was the name given by Spiritualists in the 1870s to what they believed to be a materialized spirit. The question of whether the spirit was real or a fraud was a notable public controversy of the mid-1870s. The spirit was said to have appeared first between 1871 and 1874 in séances conducted by Florence Cook in London, and later in 1874-1875 in New York in séances held by the mediums Jennie Holmes and her husband Nelson Holmes. Sir William Crookes OM PRS (1832-1919) was a British chemist and physicist who attended the Royal College of Chemistry[1] in London, and worked on spectroscopy.